Corrugated plastic drainage pipe with interrupted rib

ABSTRACT

A resilient plastic drainage pipe having annular corrugations of alternating ribs and valleys, the majority of the ribs being uninterrupted and arranged in spaced groups with certain other ribs being interrupted by a recessed wall portion of an arcuate extent greater than 90 degrees and no more than 180 degrees. The recessed wall portion is positioned at a level intermediate the peripheries of the ribs and valley portions and has holes provided therethrough for drainage of liquids from the pipe.

United States Patent [1 1 Maroschak Sept. 3, 1974 1 CORRUGATED PLASTIC DRAINAGE PIPE WITH INTERRUPTED RIB [76] Inventor: Ernest J. Maroschak, Box 878,

Roseboro, NC. 28382 [22] Filed: Jan. 11, 1973 [211 App]. No.: 322,739

Related US. Application Data [63] Continuation-impart of Ser. No. 262,103, June 12, 1972, Pat. No. 3,747,352, which is a continuation-in-part of Ser. No. 228,508, Feb. 23, 1972.

[52] US. Cl 61/10, 138/121, 138/173 [51] Int. Cl E02b 13/00, F161 11/06 [58] Field of Search 138/172, 173, 121, 155, 138/DIG. 7; 61/10, 11, 12, 13

[56] References Cited UNITED STATES PATENTS 3/1968 Fochler l38/D1G. 7 8/1969 DeGain 138/173 X 3,578,777 5/1971 DeGain.... l38/l73 X 3,658,097 4/1972 Martin l38/l2l X 3,731,711 5/1973 Bauer l38/l73 FOREIGN PATENTS OR APPLICATIONS 684,167 ll/l939 Germany 138/69 Primary Examiner-Jacob Shapiro Attorney, Agent, or Firm-Parrott, Bell, Seltzer, Park & Gibson [57] ABSTRACT A resilient plastic drainage pipe having annular corrugations of alternating ribs and valleys, the majority of the ribs being uninterrupted and arranged in spaced groups with certain other ribs being interrupted by a recessed wall portion of an arcuate extent greater than 90 degrees and no more than 180 degrees. The recessed wall portion is positioned at a level intermediate the peripheries of the ribs and valley portions and has holes provided therethrough for drainage of liquids from the pipe.

8 Claims, 3 Drawing Figures CORRUGATED PLASTIC DRAINAGE PIPE WITH INTERRUPTED RIB This application is a continuation-in-part of my copending application Ser. No. 262,103 filed June 12, 1972 entitled CORRUGATED DRAINAGE PIPE WITH PLATEAUS DEFINING RECESSES, now US. Pat. No. 3,747,352 which application, in turn, is a continuation-in-part of my copending application Ser. No. 228,508 filed Feb. 23, 1972 entitled CORRUGATED DRAINAGE PIPE.

This invention relates to resilient plastic drainage pipe of the type used underground in septic tank installations. In my earlier aforementioned application, Ser. No. 262,103, filed June 12, 1972, a corrugated plastic drainage pipe is disclosed which includes interrupted ribs having a plurality of relatively short, segmental recessed wall portions defining the interruptions therein. The present invention differs over this earlier invention in that a single recessed wall portion of an arcuate'extent of no more than 180 degress is provided defining the interruption in the interrupted ribs.

It has been found that by providing a single recessed wall portion in the interrupted rib, greater latitude is afforded in the positioning and spacing of the drainage holes in the pipe. Thus, the arrangement of the drainage holes in the pipe may be easily changed without requiring replacement or modification of the mold blocks used to form the corrugated pipe. It has also been found that by providing a single recessed wall portion of a relatively long arcuate extent rather than a plurality of relatively short, segmental recessed wall portions as in my aforementioned invention, the drainage of liquids from the pipe is facilitated by providing a larger open area or channel outside the pipe and adjacent the drainage holes for accumulation of liquids and penetration thereof into the underlying soil or gravel.

The foregoing advantages are provided in the present invention while maintaining the benefits and advantages of my aforementioned earlier invention, such as providing improved compressive strength to the pipe. The plateau nature of the recessed wall portion provides corrugation side walls which extend radially inwardly toward the axis of the pipe and interconnect the recessed wall portion with the valley portion, thereby serving to reinforce the pipe in the areas where the drainage holes are provided. Also, as in my earlier invention, the thinner construction of the recessed wall portions facilitates drilling of holes therein by more readily dissipating heat, as compared to corrugated plastic pipes not providing the recessed wall portion. Also as in my earlier invention, molding is facilitated by reducing the interior surface area of the pipe in contact with the mold plug or core, thereby reducing drag and sticking of the pipe on the mold plug.

In view of the foregoing, it is a more specific object of this invention to provide an improved corrugated resilient drainage pipe of high compressive strength so constructed as to facilitate the drilling of drainage holes therethrough and so designed as to promote the drainage of liquids therefrom.

Some of the objects and advantages of the invention having been stated, others will appear as the description proceeds when taken in connection with the accompanying drawings in which FIG. 1 is an elevation view of the underside of a corrugated plastic drainage pipe according to the invention;

FIG. 2 is a transverse sectional view of the corrugated plastic drainage pipe of FIG. 1 taken along the line 22 and showing the pipe oriented with the drainage holes on the underside of the pipe; and

FIG. 3 is a perspective view of the pipe of the present invention.

Referring now more particularly to the invention, as illustrated in FIG. 1, reference numeral 10 broadly represents acorrugated plastic drainage pipe according to the present invention which is formed from a plastic material such as polyethylene and which is of relatively lightweight construction and has a wall thickness of no greater than about l/l6 inch.

The pipe is provided with annular corrugations of alternating annular ribs 1 l and annular valley portions 12 interconnected by corrugation side walls 13, with there being about seventeen ribs and valleys per foot of pipe. The majority of ribs are of the same size and are uninterrupted and arranged in spaced groups of five with an interrupted rib 11 being positioned between adjacent groups of uninterrupted ribs. It can be seen from FIG. 1 that the ribs 11 are somewhat wider than the valley portions 12 and that the side walls 13 of the corrugations are tapered and lie in a plane inclined slightly from the vertical.

Referring now to the interrupted ribs 11', as will be seen most clearly from FIG. 2, each interrupted rib l 1' includes a recessed wall portion 14 extending partially around the rib and defining the interruption in the interrupted rib. The recessed wall portion of each interrupted rib is correspondingly arranged with the recessed wall portion in other interrupted ribs so that they are in longitudinal alignment with each other. The recessed wall portion is located at a level intermediate the peripheries of the ribs 11 and the valley portions 12 and preferably at a level which is less than half the height of the periphery of ribs 11 above that of valley portions 12. As discussed in more detail later, the recessed wall portion 14 extends over a substantial portion of the interrupted rib 11 and covers an arcuate extent greater than degrees but no more than about degrees, as indicated by arrow A in FIG. 2. Interrupted rib segment 15 comprises the remaining portion of the interrupted rib 11' and has a width and height substantially the same as adjacent uninterrupted ribs. End walls 16 extend radially outwardly from opposite ends of the recessed wall portion 14 and interconnect the recessed wall portion with the periphery of the interrupted rib segment 15, thereby defining the arcuate extent A of the interruption.

Between the end walls 16 of the recessed wall portion 14 and extending through the recessed wall portion are a series of drainage holes 20, 20a, 20b. As shown in FIG. 2, three holes are provided which are spaced approximately 60 degrees apart. It should be noted that while three holes are shown and are the preferred arrangement according to the present invention, other hole arrangements which are commonly used in the industry are easily adaptable to the invention without requiring modification of the interrupted rib structure or modification of the mold blocks used to form the corrugated plastic pipe. It will be recalled that in my aforementioned earlier invention, recessed wall portions are porvided at certain spaced areas around the pipe, thus requiring the drainage holes to be drilled only in those particular areas. According to the present invention there is considerable more flexibility afforded in where the holes may be located in the recessed wall portion and in the number of holes which may be provided. Thus, for example, two drainage holes may be provided in the recessed wall portion, if desired, instead of the three holes as shown.

The drainage holes are at least one-half inch in diameter and are preferably three-fourths inch in diameter. As illustrated, the drainage holes have a diameter greater than the width of the ribs and extend into the valley portions adjacent opposite sides of the recessed wall portions 14. Thus, the drainage holes extend through two levels of the wall of the pipe, namely, the recessed wall portions 14 on an intermediate level and the valley portions 12 on a lower level. This arrangement effectively increases the size of the drainage holes, as is best understood from viewing FIG. 3.

For aiding in properly installing the drainage pipe, sight means 30 (FIG. 2) is preferably provided longitudinally of the pipe along the surface thereof in direct opposition to the drainage hole a for visually aiding in installing the pipe in the ground with the drainage holes properly positioned lowermost. As illustrated, sight means is in the form of a painted line contrasting with the color of the drainage pipe but may, if desired, be in the form of a series of small rib portions extending longitudinally of the pipe along the outer surface'of the ribs.

The recessed wall portion 14 has an arcuate extent of no more than 180 degrees and preferably of no more than about l65-l70 degrees so that when the pipe is properly positioned underground with the recessed wall portions and drainage holes positioned lowermost, the interrupted rib segment 15 and end walls 16 shieldingly protectthe drainage holes in the pipe from soil or gravel and help to prevent blocking of the holes. The recessed wall portion located on the underside of the pipe also provides an arcuate open space or channel between the periphery of the pipe and the underlying soil or gravel which permits improved drainage of liquids from the pipe as compared to my earlier invention by presenting substantially more surrounding soil surface area adjacent the drainage holes for penetration of liquids into the soil. This cavity or chamber is provided in the lower side of the pipe while maintaining high compressive strength in this area of the pipe by providing the interrupted rib 15 on the upper side of the pipe and the recessed wall portion 14 on the underside of the pipe. Accordingly, corrugation. side walls are provided regularly throughout the length of the pipe, and these corrugation side walls serve to provide improved compressive strength in the pipe.

It should be apparent from the foregoing that an improved resilient plastic drainage pipe has been provided which has a high compressive strength, which is especially suited for accommodating a variety of drainage hole arrangements, and which also provides improved drainage of liquids from the pipe.

In the drawings and specification there has been set forth a preferred embodiment of the invention and, although specific terms are employed, they are used in a generic and descriptive sense only and not for purposes of limitation.

That which is claimed is:

l. A resilient plastic drainage pipe having spaced apart successively arranged ribs with interconnecting valley portions therebetween defining annular corrugations along the periphery of the pipe, the majority of said ribs being uninterrupted and arranged in spaced groups, certain other ribs being interrupted and being located between adjacent groups of uninterrupted ribs, each interrupted rib having an elongate recessed wall portion of an arcuate extent greater than and no more than 180 defining the interruption therein and being positioned at a level intermediate that of the peripheries of said ribs and said valley portions, side walls extending radially inwardly from opposite sides of said recessed wall portion and interconnecting the same with said valley portions, and at least one drainage hole provided in the recessed wall portion of each interrupted rib with the diameter of the hole being greater than the width of the rib.

2. A resilient plastic drainage pipe according to claim 1, wherein end walls extend radially outwardly from opposite ends of said recessed wall portion to the periphery of the interrupted rib and define the arcuate extent of the interruption.

3. A resilient plastic drainage pipe according to claim 1, wherein said drainage holes are three in number and are arcuately spaced substantially equal distances apart in the recessed wall portion of each interrupted rib.

4. A resilient plastic drainage pipe according to claim 1, wherein the periphery of said recessed wall portion is positioned closer to the periphery of said valley portion than to the periphery of said ribs.

5. A resilient plastic drainage pipe according to claim 1, wherein said uninterrupted ribs are arranged in spaced groups of five successive ribs.

6. A resilient plastic drainage pipe having spaced apart successively arranged ribs with interconnecting valley portions therebetween defining annular corrugations along the periphery of the pipe, the majority of said ribs being uninterrupted and of the same size and arranged in spaced groups of five successive ribs with an interrupted rib between adjacent groups, each interrupted rib having the major portion thereof of substantially the same size as adjacent uninterrupted ribs and with an elongate recessed wall portion of an arcuate extent greater than 90 and no more than defining the interruption therein and being positioned at a level intermediate that of the peripheries of said ribs and said valley portions, side walls extending radially inwardly from opposite sides of said recessed wall portion and interconnecting the same with said valley portions, end walls extending radially outwardly from opposite ends of said recessed wall portion to the periphery of the interrupted rib and defining the arcuate extent of the interruption, and a plurality of drainage holes provided in the recessed wall portion of each interrupted rib with the diameter of each hole being greater than the width of the rib.

7. A resilient plastic drainage pipe having spaced apart successively arranged ribs with interconnecting valley portions therebetween defining annular corrugations along the periphery of the pipe, some of the ribs being interrupted by a respective elongate recessed wall portion of an arcuate extent greater than 90 and no more than positioned at a level intermediate that of the peripheries of said ribs and said valley portions, and side walls extending radially inwardly from opposite sides of each of said elongate recessed wall 6 portions and interconnecting the same with the adjaeach of said elongate recessed wall portions with the cent valley portions. diameter of the hole being greater than the width of the 8. A resilient plastic drainage pipe according to claim rib.

7, wherein at least one drainage hole is provided in 

1. A resilient plastic drainage pipe having spaced apart successively arranged ribs with interconnecting valley portions therebetween defining annular corrugations along the periphery of the pipe, the majority of said ribs being uninterrupted and arranged in spaced groups, certain other ribs being interrupted and being located between adjacent groups of uninterrupted ribs, each interrupted rib having an elongate recessed wall portion of an arcuate extent greater than 90* and no more than 180* defining the interruption therein and being positioned at a level Intermediate that of the peripheries of said ribs and said valley portions, side walls extending radially inwardly from opposite sides of said recessed wall portion and interconnecting the same with said valley portions, and at least one drainage hole provided in the recessed wall portion of each interrupted rib with the diameter of the hole being greater than the width of the rib.
 2. A resilient plastic drainage pipe according to claim 1, wherein end walls extend radially outwardly from opposite ends of said recessed wall portion to the periphery of the interrupted rib and define the arcuate extent of the interruption.
 3. A resilient plastic drainage pipe according to claim 1, wherein said drainage holes are three in number and are arcuately spaced substantially equal distances apart in the recessed wall portion of each interrupted rib.
 4. A resilient plastic drainage pipe according to claim 1, wherein the periphery of said recessed wall portion is positioned closer to the periphery of said valley portion than to the periphery of said ribs.
 5. A resilient plastic drainage pipe according to claim 1, wherein said uninterrupted ribs are arranged in spaced groups of five successive ribs.
 6. A resilient plastic drainage pipe having spaced apart successively arranged ribs with interconnecting valley portions therebetween defining annular corrugations along the periphery of the pipe, the majority of said ribs being uninterrupted and of the same size and arranged in spaced groups of five successive ribs with an interrupted rib between adjacent groups, each interrupted rib having the major portion thereof of substantially the same size as adjacent uninterrupted ribs and with an elongate recessed wall portion of an arcuate extent greater than 90* and no more than 170* defining the interruption therein and being positioned at a level intermediate that of the peripheries of said ribs and said valley portions, side walls extending radially inwardly from opposite sides of said recessed wall portion and interconnecting the same with said valley portions, end walls extending radially outwardly from opposite ends of said recessed wall portion to the periphery of the interrupted rib and defining the arcuate extent of the interruption, and a plurality of drainage holes provided in the recessed wall portion of each interrupted rib with the diameter of each hole being greater than the width of the rib.
 7. A resilient plastic drainage pipe having spaced apart successively arranged ribs with interconnecting valley portions therebetween defining annular corrugations along the periphery of the pipe, some of the ribs being interrupted by a respective elongate recessed wall portion of an arcuate extent greater than 90* and no more than 180* positioned at a level intermediate that of the peripheries of said ribs and said valley portions, and side walls extending radially inwardly from opposite sides of each of said elongate recessed wall portions and interconnecting the same with the adjacent valley portions.
 8. A resilient plastic drainage pipe according to claim 7, wherein at least one drainage hole is provided in each of said elongate recessed wall portions with the diameter of the hole being greater than the width of the rib. 